1. Field of the Invention
The present invention relates to an ophthalmologic measuring apparatus, and particularly to an ophthalmologic measuring apparatus which performs a principal component analysis of ocular characteristic components changing by blinking, and facilitates judgment on the state of an eye, such as dry eye. In an embodiment of the invention, ocular characteristic components are obtained especially as optical characteristic components such as Zernike polynomials, optical characteristic data obtained plural times in an interval from the start point of timing when a blink starts to a point when a next blink starts are arranged longitudinally, and principal component processing is performed on the longitudinally arranged data.
2. Background Art
Hitherto, as an ophthalmologic measuring apparatus relating to dry eye, following techniques can be mentioned.
Patent document 1 discloses an ophthalmologic measuring apparatus which quantitatively measures fluorescence intensity from a cornea and tear fluid of a subject eye to which a specified fluorescence agent is applied. Patent document 2 discloses an ophthalmologic measuring apparatus which observes a color image of an interference pattern due to interference of reflected light between the front surface and back surface of a lipid layer, so that the state of the lipid layer of the subject eye, the state of flow of tear fluid and the like can be known, and a simple diagnosis of a local dry eye can be easily performed in a non-contact manner. Patent document 3 discloses an ophthalmologic tear observation apparatus in which only a signal light reflected from a tear film of a subject eye is made incident on a CCD, so that shading does not occur in an observation field, and a clear tear interference pattern without disturbance light can be observed in a wide observation field.
Patent document 4 discloses an ophthalmologic apparatus in which a subject is encouraged to blink at specified intervals while he/she is in a more natural state, a measurement result under a fixed condition is obtained, and a change with the passage of time for each individual or comparison of measurement results between different persons can be made more meaningfully.
Further, with respect to the principal component analysis, although non-patent document 1 discloses the application of the principal component analysis to the analysis of a time change in human eye wavefront aberration, the possibility of its usability is merely suggested, and a specific configuration is not clarified.
Patent document 1: JP-A-6-277179
Patent document 2: JP-A-7-136120
Patent document 3: JP-A-8-52112
Patent document 4: JP-A-2005-230328
Non-Patent document 1: “41st The Japanese Society of Ophthalmological Optics, 20th Ophthalmologic ME Society, Joint Society General Meeting, Abstracting Journal”, Sep. 3, 2005, page 42
However, in the related art, merely the time change of the ocular aberration is seen, and as the ophthalmologic measuring apparatus used for the clinic of dry eye, it can not be said that demands relating to the judgment of the state of dry eye are sufficiently satisfied.